A masked pro-Russia man and his dogs stand Thursday at barricades surrounding the Donetsk administration building in Ukraine. / Manu Brabo, AP

by Oren Dorell, USA TODAY

by Oren Dorell, USA TODAY

Members of Congress Thursday urged that Russia be hit with stronger economic sanctions to ease a worsening situation in Ukraine.

"Despite the warnings issued and sanctions imposed by the U.S. and our allies, Russia continues its aggression against Ukraine," said Rep. Ed Royce of California, the Republican chairman of the House Foreign Affairs Committee in his prepared opening remarks.

Despite a weakening Russian economy due to U.S. and European sanctions over Ukraine, the situation remains "a crisis, with violence intensifying," Royce said.

The violence and Western sanctions have caused $63.7 billion in capital to flee the country in the first quarter, the committee said. The Russian stock market has lost 25% of its value and the World Bank has warned that Russia's growth rate could become negative in the coming year.

Yet, Russian President Vladimir Putin has said that "the cost is bearable," Royce said.

"We must stop reacting to Putin's moves, while waiting patiently for the Europeans to join us," Royce said. "Instead, we must adopt a proactive strategy that will convince Putin that his aggression will have a significant and lasting cost to the Russian economy."

Rep. Gerry Connolly, D-Va., described armed clashes in the streets between pro-Russian militants and Ukrainian security forces, the shoot-down of three military helicopters and a pending sovereignty referendum scheduled for May 11.

"The situation in Ukraine has taken a grave turn for the worse in recent days," Connolly said. And despite the protestations of Putin that he's lost control over the separatists, Russia bears responsibility for what's happening, Connolly said.

"The Russian president cannot reasonably expect the world to divorce Russian intervention from the violence we are seeing in Ukraine," Connolly said.

Rep. Eliot Engel of New Jersey, the ranking Democrat on the committee, agreed that the United States needs to back Ukraine more strongly.

"The people of Ukraine are looking to us for support," he said. "We need to have their back. President Putin has to understand that his actions will have consequences. If Russia continues to increase pressure on Ukraine we need to ratchet up sanctions further."

"If we don't step up to the plate on this we can almost kiss NATO goodbye," Engel said. "Other countries are telling us they're terribly afraid of becoming collateral damage in this."

The U.S. is providing Ukraine with $255 million in aid plus $1 billion in loan guarantees, while gradually raising the economic costs for Russia "for its occupation and illegal annexation of Crimea and its continuing efforts to destabilize eastern and southern Ukraine," said Victoria Nuland, assistant secretary of state for European and Eurasian Affairs.

To date, Russia "has fulfilled none of its commitments" to reduce tensions in Ukraine, Nuland said.

While Putin's pledged Wednesday to pull back troops, his country continues to provide material support, weapons, funding and coordination and to send Russian agents into Ukraine, she said.

Among people detained in Odessa were those whose papers indicated they came from Transnistria, Crimea and Russia, and the U.S. has "high confidence that Russia's hand is behind this instability," Nuland said.

The 3,300 U.S.-supported Ukrainian election observers, and 500 observers from the Organization for Security and Cooperation in Europe, will make Ukraine's election the "best-observed" vote in Europe since the end of the Cold War, she said.

The hearing occurs as a Ukrainian security official Thursday pledged to continue its fight against pro-Russian separatists after a council of the self-proclaimed People's Republic of Donetsk voted to go ahead with a referendum on secession from Ukraine Sunday despite Putin's call for a delay.

Andriy Parubiy, Ukraine's Secretary of the National Security and Defense Council, told journalists minutes later about the announcement in Donetsk that Ukraine's anti-terrorist operation will continue in the country's eastern regions.

A new report released Thursday by Pew Research shows a majority of Ukrainians - 77% - want their country to remain a single, unified nation. That holds true even in the largely Russian-speaking east, according to the survey, conducted by Pew in Ukraine.

Rep. Dana Rohrabacher, R-Calif., questioned the costs to the USA of getting involved in what he described as a conflict between what he said are two undemocratic forces in Ukraine.

The situation in Ukraine "is a lot murkier" than "a simple case of Russian aggression," Rohrabacher said. "We should not ‚?¶go into debt in order to borrow more money to help Ukraine."